Auto gearbox problem

hello,

got a 97 300tdi automatic, when accelerating or even just coasting in gear it occasionally loses drive. Its only for a slight second but it really causes problems when trying to get upto speed.

Its either losing drive or swapping between gears very quickly like its unsure what to be in.

For example travelling at like 65 you will get like the occasional hesitation as if its kicking down and back up again really quickly

Any ideas?

cheers

1st Thing i would do is drain the auto box oil into a clean container and see if there are any bits in it,

if not put it back in,

if there are bits it may be the clutches falling apart.

when was the atf last changed?

Its not been changed whilst I've had it, about 6 months 3000miles. Its always been on my to do list, engine oil has already been done a few times but this being my first auto i've put off messing with it.

I have checked the atf level a few times and its ok and looks and smell alright, Ill drop the fluid as soon as and see what its like, cheers.

Annoying thing is, you can drive it really hard and it pulls fine through all gears and you can float along at 55 no problem its just occasionally you get that hesitation

I have the same problem but I think it's an engine problem. You don't have the direct relationship between engine speed and drive speed in the auto box, so it's not quite clear cut, but I've been treatingit as an engine problem so far. Only had disco a week so far though!

Keep an eye on this thread too

http://www.landyzone.co.uk/lz/f8/new-disco-hesitation-problem-higher-rpm-under-high-load-205389.html

Steve2a said:

hello,

got a 97 300tdi automatic, when accelerating or even just coasting in gear it occasionally loses drive. Its only for a slight second but it really causes problems when trying to get up to speed.

Its either losing drive or swapping between gears very quickly like its unsure what to be in.

For example travelling at like 65 you will get like the occasional hesitation as if its kicking down and back up again really quickly

Any ideas?

cheers

Click to expand...

It sounds like it might be the Torque Converter unlocking and locking again. Torque Converter (TC) operates in top gear above 52mph.

Does it happen when you are above 52mph and trying to accelerate up a hill for example?

That's exactly what happens on mine, for definite! It sounds like the same thing the OP was describing too!

My own autobox fluid looks very clean and doesn't smell burnt, it also looks to be at the correct level. I was surprised that it was a golden colour though, when I was expecting cherry red ATF fluid. Not sure whether it's a different fluid used in these autoboxes?

IF that's what is happening it is normal behaviour and does not indicate a fault.

really? It kind of sucks though especially when you're trying to overtake going uphill!

tombardier said:

really? It kind of sucks though especially when you're trying to overtake going uphill!

Click to expand...

These are not sports cars, relax and enjoy.

I understand that, but if it's not a fault per se, then it's definitely a very poor feature! Nobody wants to put their foot down and have their vehicle fail to pull consistently and predictably.

tombardier said:

My own autobox fluid looks very clean and doesn't smell burnt, it also looks to be at the correct level. I was surprised that it was a golden colour though, when I was expecting cherry red ATF fluid. Not sure whether it's a different fluid used in these autoboxes?

Click to expand...

A couple of observations:

1. The oil in these auto boxes should be Dexron IID or III. This is normally cherry red, so I wonder if some previous owner has put in different oil. I would change it at the earliest opportunity, just in case they've put the wrong stuff in .

2. When checking the autobox oil level, there is a specific procedure to follow: start with a cold engine, cycle the gearobox through all position then back to park, THEN use the engine bay dipstick to check the oil level - it should in between the two marks.

General comments:

These gearboxes take 9 ltrs in total, but you can only get out approx 4.5 ltrs at any one time, so most peeps on here would do an oilchange, run the car for a few miles and then do it again.

Obviously you won't get absolutely all the old oil out but it will be sufficiently diluted to reduce the chance of problems.

tombardier said:

I understand that, but if it's not a fault per se, then it's definitely a very poor feature! Nobody wants to put their foot down and have their vehicle fail to pull consistently and predictably.

Click to expand...

They do work consistently and predictably, you just need to understand them to get the best from them.

For example, if you are towing a heavy load in hilly country it can better to select '3' rather than 'D' - this stops the TC locking and unlocking and inadvertently going into top gear and then coming out again.

You would do exactly the same with a manual 'box wouldn't you? You wouldn't just leave it in 5th all the time?

OK. I'm going to ditch the oil and go for some nice cherry juice I think!

Are you saying that the gearbox is switching down because it hasn't got enough torque to stay high - thus the vehicle is slowing down, and then it's switching up again because the torque starts accelerating back to the changeover speed? That kind of makes sense, but is still annoying.

Best start with changing the fluid

has anyone here ever tried the trick where you undo the oil cooler pipes and feed in new oil whilst ditching the old through those pipes? might get a more complete flush. I know someone who did it on a granada once!

tombardier said:

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Are you saying that the gearbox is switching down because it hasn't got enough torque to stay high - thus the vehicle is slowing down, and then it's switching up again because the torque starts accelerating back to the changeover speed? That kind of makes sense, but is still annoying.

.....................................

has anyone here ever tried the trick where you undo the oil cooler pipes and feed in new oil whilst ditching the old through those pipes? might get a more complete flush. I know someone who did it on a granada once!

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The autobox in D works on hydraulic pressure, in part this is generated by the demand put on the engine.

There are valves in the gearbox which are designed to open at close at certain pressures. This is separate to the "kick-down" function on the accelerator pedal.


I have a mate who uses a small electric pump and does this, you just have to be VERY careful not to introduce any debris in the oil circuit.

I've researched a bit more, and it seems that the japs use the golden coloured ATF, and mine being a jap import - that explains it! It does look clean I must say

flushing out an older gear box isnt necessarily a good thing ,normal 4-5 litre change is adequate if oil is filthy then box is failing and oil change is pointless,checking adjustment of kick down cable can help ,clean oil usually means box is fine physically operation of govenor and vales etc would need hydraulic pressure test

It's got 55k miles from new. I can't find the service interval for autobox gear changes anywhere. I know all the stuff about changing the oil causing problems on older boxes, but if I keep up regular changes, surely that'd be quite a good thing?

yes it is a very good thing,its more of an issue were people havent and then flushing box over quickly